This week I have probably uttered every one, except the last, of these phrases; more than once – and it’s only Tuesday. I desperately try to get my children to watch their manners, to observe a code of conduct that they think is pointless, irritating, and generally bananas. What’s more, I thought exactly the same when my Dad used to lecture me. I had a theory that what adults called ‘manners’ was just senseless ritual, a way for the head ape to assert his authority, all the more so by demanding pointless actions.

So, like all kids, I resisted and ignored the call to manners, and was berated from high-chair to high school. So why, now, do I find myself demanding the same behaviour from my kids? Is it learnt parenting? Am I desperate to be recognised as head ape? Or is there something more instinctual at play?

There’s no doubt that that the list of manners that we’re brought up to observe is maddening but recent research shows that manners might just be one of the most important evolutionary behaviours we possess.

Human socialisation has been a key to our evolution to uber-species. Yet, through contact, we also threaten each other with hostile microbes, viruses, and potential diseases.

‘You are a walking bag of microbes,’ explains Dr Val Curtis writing in the New Scientist, ‘With every exhalation you might emit millions of influenza viruses, and your handshake might transfer salmonella bacteria or scabies mites… so how can we get close enough to share benefits but avoid sharing our microbes? … Manners dictate that if I want to interact with you I should stay a safe distance; far enough away not to spray you with microbe laden saliva.’

An expert on disease control at the London School of Hygiene and Tropical Medicine, Dr Curtis argues that manners make sure we are clean and cover the parts of the body where microbes may lurk. For the same health preserving reasons, manners also dictate that we share food but not food we’ve already bitten and clean our dwellings before inviting others in. Failure to comply may damage your reputation and ostracise you from the benefits of our powerfully social species

Studies have shown that our expressions of disgust are made visually and audibly to shame those who don’t meet our social hygiene expectations. We also make them so we can train our children even before language.

Even manners’ less hygiene focussed faux altruism provides a positive gain. ‘The child who passes a plate of food before serving herself,’ Dr Curtis says, ‘is showing that she can control her selfish tendencies. In effect, she is saying: “Look how well my mother taught me. If I can show such self-control now, how useful a member of this society I will be in the future. In the meantime, you can safely do business with my family.” The child taught restraint with cake now by her mother would be likely to receive a greater total of cooperative cake in her lifetime.’

For Curtis manners are a ‘proto-morality, a set of behaviours that we make “second nature” early in life so that we can avoid disgusting others with our parasites and our antisocial behaviour. ‘

‘We don’t rationally calculate how to avoid inflicting our pathogens on others, nor do we consciously calculate that a small courtesy now might lead us to a big trading opportunity later. Instead, we have vague intuitions that it would be better not to disgust a guest by appearing unkempt or by offering them a dirty towel, and we follow the rules of politeness that were drummed into us as children. When we fail in these civilities, the disgust shown by our interlocutor provokes shame and teaches us not to repeat the offence.’

Sociologists have pointed to manners as possessing symbolic gestures indicating membership of a tribe or class. People who observe the same manner rituals are more likely to assume a bond and trust each other. But in these more hygienically aware times, and as class barriers are brought down, do manners still have a place?